<!DOCTYPE html>
<html lang="zh-CN">

<head>
    <meta charset="UTF-8">
    <title>css三大特性</title>
    <link rel="stylesheet" href="./index.css">
    <style>  
        h1 {
            color: aqua;
        }
    </style>
    
</head>

<!-- 
层叠性
继承性
优先级
 -->
<body>
    <h1 id="atguigu">我是span2</h1>
</body>

</html>